Differential Diagnosis for Constipation and Thin Bloody Stools
Single Most Likely Diagnosis
- Hemorrhoids: This condition is a common cause of thin bloody stools and can also lead to constipation due to pain and discomfort during bowel movements, causing patients to strain or avoid defecation.
Other Likely Diagnoses
- Anal Fissure: Similar to hemorrhoids, anal fissures can cause pain and bleeding during bowel movements, potentially leading to constipation.
- Diverticulitis: While more commonly associated with left lower quadrant pain, diverticulitis can cause changes in bowel habits, including constipation, and may lead to bloody stools if there is significant inflammation or erosion into a blood vessel.
- Inflammatory Bowel Disease (IBD): Conditions like ulcerative colitis and Crohn's disease can cause constipation and bloody stools, especially if the disease is localized to the rectum or sigmoid colon.
Do Not Miss Diagnoses
- Colorectal Cancer: Although less common, colorectal cancer is a critical diagnosis not to miss, as it can present with changes in bowel habits, including constipation, and bloody stools.
- Infectious Colitis: Certain bacterial infections (e.g., Clostridioides difficile, Salmonella, Shigella) can cause constipation and bloody stools, and while Streptococcus viridans is less commonly associated with gastrointestinal infections, other bacteria are more likely culprits.
- Ischemic Colitis: Reduced blood flow to the colon can cause sudden onset of abdominal pain, constipation, and bloody stools, and is a medical emergency.
Rare Diagnoses
- Intussusception: A condition where a part of the intestine slides into an adjacent part, which can cause bowel obstruction and bloody stools. It's rare in adults but can occur.
- Angiodysplasia: Vascular malformations in the colon can cause chronic, occult, or sometimes overt bleeding, potentially leading to changes in bowel habits.
- Streptococcus viridans Infection: While Streptococcus viridans is more commonly associated with endocarditis and dental infections, it is theoretically possible for it to cause a gastrointestinal infection, although this would be extremely rare and not typically the first consideration for constipation and thin bloody stools.